This disclosure relates generally to the field of table cutting machines for wood or metal products. More specifically, the disclosure relates to automated sawing machines using band or circular saws.
Automatic sawing machines are known in the art to possess several automatic or semi-automatic features. Typically, these include, but are not limited to: automatic advancement of a blade into a workpiece and subsequent retraction of the blade to a home position; automatic actuation of a workpiece shuttle to pull a workpiece in the direction of work flow to a sawing position; the automatic opening and closing of stationary and shuttle vises; and a means to cut several pieces to the same length and angle of cut.
Automatic sawing machines must operate at very high tolerance levels. High tolerances require the ability to position the workpiece within, for example, 0.0002″. While achieving these fine tolerances is possible mechanically using known methods, there is no known, effective automated way to monitor the motion of the workpiece relative to the positioning device to ensure that the cut piece will be of the proper length. As a result, in order to achieve high tolerances, operators must physically measure the workpiece. This manual step slows production and demands a high degree of operator skill and accuracy.
While automatic sawing machines are highly automated, current machines lack the ability to monitor some aspects of machine operation. For example, materials with irregularities, such as burs, can become caught on some structure of the saw while being moved into a cutting position, resulting in slippage between the material and the vise. Additionally, bundles of material are sometimes held together with straps. The straps can also become caught on some structure of the saw while the bundle is being moved into a cutting position, causing the workpiece to slip relative to the vise. Such slippage could result in the workpiece being cut to a length that is out of tolerance.